Cross platform build fix for SSIM (part 2)

Data alignment fix for SSIM.

WebRtc_UWord64[2] wasn't always aligned to 128 bytes, which
is necessary for _mm_store_si128.  By declaring the 
variable as __m128i it will always be 128 bytes aligned.

Related to issue 239013.
http://webrtc-codereview.appspot.com/239013/
Review URL: https://webrtc-codereview.appspot.com/375004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@1582 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed